Neurologic system, overview and cells
Terms
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- parts of CNS
-
brain
spinal cord -
parts of PNS
(peripheral nervous system) -
cranial nerves
spinal nerves - carry impulses to CNS
-
afferent pathways
ascending pathways - transmit impulses away from CNS
-
efferent pathways
descending pathways - innervated by efferent pathways
- effector organs
- example effector organs
-
skeletal muscle
cardiac muscle
smooth muscle
glands -
divisions of PNS
(peripheral nervous system) -
somatic
autonomic - regulated by somatic nerves
- voluntary muscles
-
regulates body's internal environment
(glands, involuntary muscles) - autonomic nervous system (ANS)
-
divisions of ANS
(autonomic nervous system) -
sympathetic
parasympathetic - primary cell of nervous system
- neuron
-
provide support and nutrition for neurons
in CNS - neuroglial cells
-
provide support and nutrition for neurons
in PNS - Schwann cells
- neuroglial and Schwann cell functions
-
support, nutrition
incr. speed of impulses
role in memory - required for glucose uptake outside CNS, not in CNS
- insulin
- Nissl substances
-
endoplasmic reticulum and ribosomes
in the neurons - type of neurons that continue to divide throughout life
- olfactory
- location of most cell bodies
- CNS
- name for packed cell bodies in CNS
- nuclei
- groups of cell bodies in PNS
-
ganglia
plexuses - receptive portion of neuron, receives and continues conduction of impulse
- dendritic zone
- carry nerve impulses away from the cell body
- axon
-
cone-shaped, Nissl-free area of axon
where it leaves cell body - axon hillock
- insulating lipid covering of axon, incr. conduction rate
- myelin
- interruptions in neurilemma and myelin sheath, site of axon branching
- nodes of Ranvier
- forms and maintains myelin sheath
- Schwann cells
- conduction if tightly wrapped myelin (myelinated neuron), ions flow between segments instead of along length
- saltatory conduction
- larger axons conduct impulses (faster, slower)
- faster
-
four neuron configurations based on
projections from cell body -
unipolar - one, early branching (retina)
pseudounipolar - axon into CNS, dendrites away from CNS (sensory)
bipolar - two (to rods/cones)
multipolar - multi (motor) - three functional types of neurons
-
sensory (afferent, pseudounipolar)
motor (efferent, multipolar)
associational (btwn neurons, multipolar) -
transmit impulses from
CNS to effector organ - motor neuron
-
transmit impulse from
sensory to motor neuron -
associational neurons
(interneurons) - sensory receptor for pain
- nicoceptor
- sensory receptor for body position
- proprioceptor
-
neuroglia that fill spaces between
neurons and blood vessels in CNS - astrocytes
- deposit myelin in CNS
-
oligodendroglia
(oligodendrocytes) - remove debris in CNS
- microglia
-
if this is intact, damaged motor axon
can regrow to distal connection - neurilemma
- if membrane potential change is insufficient, no action potential is generated: an ___ ___ ___ response
- all-or-none response
- region between adjacent neurons
-
synapse
synaptic cleft - four types of synaptic connections
-
axoaxonic (btwn axons)
axosomatic (axon to cell body)
axodendritic (axon to dendrite)
dendrodendritic (dendrite to dendrite) - transmission across synapse is through _________ and moves in _____ direction(s)
-
neurotransmitter chemicals
one - where neurotransmitters are formed
- synaptic boutons
- consequences of neurotransmitter binding
-
excitation (EPSPs)
inhibition (IPSPs) - effects of successive impulses received at same synapse
- temporal summation
- combined effects of impulses a single neuron transmits to different synapses at the same time
- spatial summation
- effect of EPSPs on membrane potential
- facilitation
- sites of acetylcholine neurotransmission
-
ANS synapses
brain
spinal cord
skeletal muscle - sites of norepinephrine neurotransmission
-
sympathetic ANS synapses
brain
spinal cord - sites of serotonin neurotransmission
-
brain
spinal cord - sites of dopamine neurotransmission
-
ANS synapses
brain - sites of substance P neurotransmission
-
nicoceptors
brain
spinal cord
GI tract